


UF Relationship

by Shadow_of_Quill



Series: Socketfucking [4]
Category: Undertale (Video Game)
Genre: Fellcest - Freeform, M/M, consensual mind-control, socket-fucking
Language: English
Status: Completed
Published: 2016-12-23
Updated: 2016-12-23
Packaged: 2018-09-11 12:31:30
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 869
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8979853
Author URL: https://archiveofourown.org/users/Shadow_of_Quill/pseuds/Shadow_of_Quill
Summary: How things work between the FellBros.





	

**Author's Note:**

  * For [Askellie (NadaNine)](https://archiveofourown.org/users/NadaNine/gifts).



> The second fic I - no, wait. This is the _third_ fic I submitted to Askellie’s tumblr.

**Sans kneels before his brother.**

Papyrus was almost twenty before he learned that there were other openings he could fuck Sans in, learned what Sans’ hands were busy doing when Papyrus fucked his eyesocket.

It wasn’t long after he learned that before they started experimenting.

Sans likes it best when Papyrus has him bent over something, driving into him with one fist tight around his cock and making him lose his mind.

Papyrus likes it best when they’re facing each other, and he can watch Sans enjoy what they do, see his pleasure.

They never speak about it, never admit to each other what they like or want or need.

They’re both terrified that their answers wouldn’t match.

**Papyrus’ cock is hot, pulsing with the beat of his soul. Sans rubs his face against it, relishing the tingle from their magic interacting.**

“YOU NEED TO HAVE SOMETHING THAT ISN’T ME,” Papyrus said, and Sans has to obey him, so he found himself some notebooks and continued working on temporal equations.

It was oddly fun without Gaster driving him.

They needed to work, they needed money, and scientists were paid so much better than unskilled labour; neither of them spoke about it (so much of their lives revolve around the things they refuse to say) but they both recognised that Sans could bring in far more money if he went to be a researcher or theorist at a laboratory.

Sans made it as far as the doorway before he locked up.

The monsters there wouldn’t know, _couldn’t_ know about socketfucking and what it _did_ to a skeleton, he wouldn’t be risking himself, he’d be perfectly safe -

He couldn’t.

He just couldn’t.

The worst part was seeing Papyrus blame _himself_ for not realising how weak Sans was, instead of blaming Sans for _being_ so weak.

Papyrus went to join the Royal Guard the next day, dragged Sans with him and forced him to become a sentry, working under Papyrus’ direct supervision.

He wouldn’t let Sans throw the notebooks out.

Sans still feels guilty every time he adds to them.

**“YOU MAY TAKE IT IN,” Papyrus says, and Sans moans with relief as he finally leans forwards, finally feels his brother penetrate his eyelight.**

Sans didn’t go to Grillby’s at first.

“I’D HAVE THOUGHT YOU’D CONSIDER IT PRECISELY TO YOUR LOW TASTES,” Papyrus said disdainfully.

“sure, but you don’t want me there, and you’ve got responsibility,” Sans said easily.

He’ll never understand why the simple explanation made papyrus freeze, made him jerk and stare at Sans as if he’d said something deeply disturbing.

“SANS.” Papyrus _hesitated_. “YOU ARE - AWARE - OF WHAT YOU WANT…?”

“‘course i am, boss. couldn’t be myself if i wasn’t,” and Sans is so grateful for the humming in his bones _demanding_ that he be himself, “but you’re the one making the decisions.”

Sans always drinks too much, because he can’t make his own decisions and Papyrus doesn’t want him to drink at all _but_ he wants Sans to act for himself, so no one is deciding when he’s had enough and cutting him off.

It’s fine. Skeletons don’t get hangovers. And Papyrus is always so _relieved_ when Sans does something because _he_ wants to and not because _Papyrus_ wants him to.

**Sans loves these times when his mind is literally full of Papyrus.**

The collar tells everyone that Sans is _owned_. More than that, it tells them that he’s _willingly_ owned, when Papyrus lets Sans out of his sight so often and Sans never once tries to remove it.

None of the monsters they meet ever recognise the red hollows under Sans’ eyesockets for what they are, places where his bones have been permanently stained by his brother’s magic. They wouldn’t understand the meaning if they did.

It’s fun to walk around wearing his brother’s collar, but it’s hotter than Hell to walk around with his brother’s cumstains on his face for everyone to see and know that no one recognises what they are.

**Sans loves Papyrus’ orders, not least for their familiarity; OBEY ME AND ONLY ME, ENJOY THIS, BE YOURSELF. He’s not sure his magic would even accept new orders by now, not when these have been fucked into him so often for so long. (THAT’S THE PURPOSE, Papyrus doesn’t need to say.)**

Grillby eyes Sans, sometimes. Sans has caught himself eyeing Grillby back.

Papyrus offered to let him, jaw tight and eyelights not-quite-looking-at-Sans. “IF YOU TRULY DESIRE THE BARTENDER, I WILL PERMIT YOU TO INDULGE.”

Sans doesn’t know if he’d want to go further than looking even if there wasn’t this undefined thing between him and his brother making Papyrus his _everything_. “nah, thanks. ’m good.”

Papyrus screws him into the mattress every time he remembers making that offer, moving with greedy possessiveness that belies the soft whisper, “If you want, I’ll allow you to”. If Sans feels underappreciated, he’ll remind Papyrus of it just for that - remind himself that Papyrus cares enough about Sans’ happiness that he makes the offer, _will_ make the offer every time.

**Sans loves Papyrus. And every time Papyrus comes in him, paints his skull and thoughts with intent carried in liquid magic, Sans knows again that Papyrus loves him.**


End file.
